Imagine a winter where two respiratory viruses team up to challenge healthcare systems across the Americas. That's the reality we're facing right now, as the Pan American Health Organization (PAHO) sounds the alarm on the simultaneous spread of seasonal influenza and respiratory syncytial virus (RSV). This double threat could overwhelm hospitals and clinics during the remaining winter months in the Northern Hemisphere, leaving many vulnerable. But here's where it gets even more concerning: this isn't just a typical winter season.
In a recent alert (https://www.paho.org/en/documents/epidemiological-alert-simultaneous-circulation-seasonal-influenza-and-respiratory), PAHO updates its earlier warning from December 4, 2025 (https://www.paho.org/en/documents/epidemiological-alert-seasonal-influenza-americas-region-end-2025-season-southern), which predicted an earlier and more intense respiratory season than usual. Since October 2025, influenza activity has been steadily climbing worldwide, with the A(H3N2) strain leading the charge. Several Northern Hemisphere countries are already seeing early signs of seasonal activity, while RSV cases are also on the rise.
In the Americas, the situation is particularly worrisome. Influenza positivity rates remain above 10% in the Northern Hemisphere, with significant increases in North and Central America. The Caribbean is seeing even higher rates, approaching 20%, with A(H3N2) dominating. And this is the part most people miss: while the overall severity of the flu season is similar to previous years, some countries are experiencing activity levels—measured by flu detection and outpatient visits for flu-like symptoms—that surpass recent seasons.
Take the United States, Canada, the United Kingdom, and Spain, for example. These countries are reporting an early and rapid start to the flu season, with more people, especially children, visiting outpatient clinics. Hospitalizations are also rising, particularly among older adults. While no excess deaths have been reported so far, the gradual increase in RSV cases could further strain healthcare systems, making continuous monitoring crucial to adjust response plans.
"The dual circulation of influenza and RSV is a major challenge," explains Dr. Marc Rondy, PAHO Regional Adviser in Epidemiology of Epidemic- and Pandemic-Prone Diseases. "We must prioritize vaccination, which protects against severe cases requiring hospitalization, and maintain close surveillance to prevent larger outbreaks and avoid hospital overcrowding."
PAHO highlights that interim studies show current flu vaccines are effective in preventing hospitalizations (30–40% in adults and a remarkable 75% in children). They urge countries to achieve high vaccination coverage, especially among priority groups like children, pregnant individuals, older adults, and those with chronic conditions. But here's a thought-provoking question: Are we doing enough to ensure equitable access to vaccines across all communities?
To tackle this dual threat, PAHO recommends that countries in the region:
- Strengthen integrated surveillance of influenza, RSV, SARS-CoV-2, and other respiratory viruses, reporting weekly data to FluNET and FluID for regional and global monitoring.
- Prepare and adjust health service response plans to handle potential simultaneous increases in flu and RSV cases and hospitalizations.
- Prioritize flu and COVID-19 vaccination for at-risk groups, including older adults, young children, pregnant individuals, those with chronic conditions, and healthcare workers.
- Implement RSV prevention strategies, such as maternal vaccination and long-acting monoclonal antibodies for newborns and infants, following PAHO/WHO guidelines.
- Enhance risk communication, promoting essential preventive practices like handwashing, covering coughs and sneezes, wearing masks indoors when symptomatic, staying home when sick, and seeking prompt medical care for severe symptoms.
These simple yet effective measures can protect you and your loved ones, especially young children and older adults. So, what steps are you taking to protect yourself and your community this winter? Share your thoughts in the comments below—we'd love to hear your perspective on how we can collectively navigate this challenging respiratory season.
